/*
 function sum(a,b){
 var h = a + b;
 return h;
 }
 alert(sum(11,12));
 alert(sum(11,15));*/

/*
function sum1(a,b){
    alert(a + b)
}
alert(20 + 20);*/

/*
function sum2(a,b) {
    return a+b
}
alert(sum2(40,50));
console.log(sum2(40,50));
*/
/*
var kop = document.getElementById("kop");
//获得这个Html
console.log(kop);
//获得这个标签里面的内容
console.log(kop.innerHTML);*/

/*var textt = document.querySelector("#kop");
var text = document.querySelector(".text");
textt.innerHTML = text.innerHTML;
text.innerHTML = "第二个Hollow";*/


/*
var stu = {};

stu.name = "小明";
stu.sex = "男";
stu.fui = "18";
/!*console.log(stu);
 console.log(stu.name);
 alert(stu.name)*!/
stu.say = function () {
    return "我叫" + this.name+"是个" + this.sex+"孩子今年"+this.fui+""
};
console.log(stu.say());
*/
/*function myFunc(nums1, nums2) {
    var sum = nums1 + nums2;
    document.getElementById('sum').style.color = 'red';
}*/

/*var nem1 = "10";
console.log(parseFloat(nem1));
console.log(nem1);
console.log(Number(nem1));


var nem2 = 20;
console.log(nem2);
console.log(String(nem2));

var u = undefined;
console.log(isNaN(u));*/


var p = Math.PI;
console.log(p);
var n1 = prompt("请输入圆的半径");
n1 = parseInt(n1);
document.querySelector("#a").value = n1;
document.querySelector("#b").value = 2*n1*p;
document.querySelector("#c").value = n1*n1*p;
if (Number(n1)){
    console.log(n1);
}else{
    alert("请输入数字");
}

